Steel slag handling system and method for using same

ABSTRACT

There is disclosed herein apparatus and method for handling molten steel slag produced in a steelmaking furnace by cooling and granulating the slag on a continuous basis through interception of a stream of molten slag with a jet stream of water having particularly specified characteristics of shape, velocity and flow, and transportation of the granulated slag to a remote location as a slag/water slurry.

United States Patent [72] Inventor John J. Grady New Florence, Pa.

[21 Appl. No. 826,779

[22] Filed May 6, 1969 [45] Patented Sept. 21, 1971 [73] AssigneeInternational Steel Slag Corporation Pittsburgh, Pa.

Continuation of application Ser. No. 535,143, Mar. 17, 1966, nowabandoned which is a continuation-in-part of application Ser. No.126,792, June 28, 1961, now abandoned which is a continuation-in-part ofapplication Ser. No. 428,519, Jan. 27, 1965, now Patent No. 3,316,075,dated Apr. 25, 1967, which is a continuation of application Ser. No.485,037, Sept. 3, 1965, now abandoned which is a continuation-in-part ofapplication Ser. No. 304,932, Aug. 27,

1963, now abandoned. Y i T 1541 STEEL sLAG'nXNnuNG SYSTEM AND METHOD FORusmo SAME 26 Claims, 3 Drawing Figs.

52 US. Cl 65/19, 'a ,LZ9 4L36 [51] Int. Cl C03b 19/08 [50] Field ofSearch 65/19, 20, 141; 264/1 1 [56] References Cited UNITED STATESPATENTS 1,888,394 11/1932 Schol 65/141 3,316,075 4/1967 Grady.. 65/193,374,999 3/1968 Burch 65/141 Primary Examiner-S. Leon Bashore AssistantExaminer-Robert L. Lindsay, Jr. Att0rney-LeBla.nc and Shur ABSTRACT:There is disclosed herein apparatus and method for handling molten steelslag produced in a steelmaking furnace by cooling and granulating theslag on a continuous basis through interception of a stream of moltenslag with a jet stream of water having particularly specifiedcharacteristics of shape, velocity and flow, and transportation of thegranulated slag to a remote location as a slag/water slurry.

PATENTED SEPZ] |97| 3.607.168

' SHEET 1 or 2 iii amaze.

By JOHN J. GRADY ATTORNEYS PATENTED SEPZI 9n SHKET 2 BF 2 Not INVENTORJOHN J. GRADY STEEL SLAG HANDLING SYSTEM AND METHOD FOR USING SAME Thisapplication is a continuation of my earlier filed copending application,Ser. No. 535,143, filed Mar. 17, 1966, and now abandoned, entitled STEELSLAG HANDLING SYSTEM. Application Ser. No. 535,143, in turn, is acontinuarlon-in-part of my earlier filed copending application, Ser. No.126,792, filed June 28, 1961, and now abandoned, entitled STEEL SLAGREMOVAL SYSTEM, and also of my copending application Ser. No. 428,519 onSTEEL SLAG HANDLING SYSTEM filed Jan. 27, 1965, now US. Pat. No.3,316,075, issued Apr. 25, 1967 as a continuation-in-part of saidapplication Ser. No. 126,792, and also of my copending application Ser.No. 485,037 filed Sept. 3, 1965, and now abandoned, as a continuation ofsaid application Ser. No. 428,519, and also of my copending applicationSer. No. 304,932 filed Aug. 27, 1963, and now abandoned as acontinuation-in-part of said application Ser. No. 126,792.

The present invention relates to a system for more efficient, faster andmore economical handling and removal of slag discharged fromsteel-making furnaces. More especially this invention relates to newimproved methods and apparatus for converting molten slag dischargedfrom a steel furnace into a granular mixture of ferrous and slagparticles of relatively small size and low temperature, and rapidlyremoving and transporting the resultant granular mixture from thefurnace building by hydraulic means without disrupting (during) thesteel-making operation, for reclaiming of usable ferrous material andother suitable disposal at a point removed from the furnace.

For some years, steel in large quantities has most commonly been made inopen hearth furnaces, in which ingredients such as scrap iron, pig iron,hot molten iron from blast furnaces, ore, limestone, etc., are meltedand refined to produce molten steel. A substantial quantity of slag isformed over the molten steel bath in the open hearth furnace and playsan important part in the steel-making process. Typically, the slagconstitutes about one-fifth of the total charge to the furnace in aheat; hence, in a modern open hearth furnace having a capacity of 350tons per heat, about 65 to 70 tons of slag are formed and must bedisposed of within a relatively short time. Generally, a modern openhearth plant contains to stationary furnaces of 200 to 350 ton capacity,which are substantially continuously operated on staggered heat cycles,so that a tremendous amount of slag must be removed from the furnacebuilding each day. Efficient quick removal of such large quantities ofslag from adjacent the steel-making furnaces and out of the furnacebuilding is a longstanding major problem in steel manufacture; and thisproblem has been greatly accentuated by development of modern techniquesmaking is possible to produce substantially greater quantities of steelper heat in a substantially shorter time with existing furnaces.

For a long time, it has been a common practice in leading mills todischarge steel slag into slag pots removed from the furnace room byrail cars, or equivalent means, to a suitable disposal area where theslag was dumped, whereafter the pots are returned to theiraforementioned positions adjacent the furnace.

However, this slag-pot system has proven inadequate and unsatisfactoryfor removal of greater tonnages of slag in less time, as furnacecapacity increased and melt time decreased. Consequently, some leadingopen hearth steel plants have adopted a system in which part of the slagis front flushed" from the center furnace door under the furnace to thepit side, and the remainder of the slag is flushed from the steel ladleto the pit floor when the furnace is tapped. Thereafter, highlift"tractors and heavy-duty trucks are used to remove the slag from the pitside of the open hearth furnace building when the steel ladle is removedafter pouring the heat. (This current system is illustrated in FIGS. 1-3of my aforesaid copending application, Ser. No. 126,792.) With a heattime of about 8 to 8-% hours for a 350-ton open hearth furnace, about 60to 70 tons of hot slag must be removed from below and behind thefurnace, loaded, trucked to a disposal point, unloaded, etc., in about 1to l-% hours. There are, however, serious shortcomings of this approachwhich can and do cause loss in furnace operating time, besides the needfor substantial equipment and maintenance.

-The need for round-the-clock removal of high tonnages of slag has ledto use in one of the most modern United States open hearth shops of atractor wagon capable of hauling 30 tons of hot slag, loaded by highlifttractors. This, however, involves problems similar to those involvedwith the above-mentioned highlift and truck system for handling steelslag (more fully discussed in my aforementioned parent application Ser.No. 126,792 with reference to FIGS. 1-3 thereof).

The problems of handling and removing steel slag have been seriouslyincreased by the steel industrys rapid adoption, within the past fewyears, of oxygen steel-making furnaces, sometimes called OSM or BOFfurnaces. These furnaces are capable of producing steel in tremendousquantities in short heat times; for example, it is possible to produce240 or more tons of steel in about 27 minutes, tap to tap (compared to 6to 8 hours tap to tap for modern open hearth furnaces). However, suchoxygen steel furnaces also form large quantities of slag in the order of12-16 percent of the heat tonnage. Thus an OSM or BOF furnace producingabout 250 tons of steel in 1b hour will also generate about 37.5 tons ofmolten slag in Va hour. Yet, these vast quantities of molten slag mustbe removed from the furnace and furnace building in minimal time forcharging and running the next heat; and it is important that slaghandling and removal not penalize the tap-totap" capacity of the furnaceand mill production.

However, the prevailing method of handling and removing molten slag fromOSM and BOF furnaces is by use of a multiplicity of costly slag potsmoved by cranes and/or rail cars from the furnace to a relatively remoteslag dump. These present multistep batch methods of handling OSM or BOFsteel slag are not only costly from the viewpoint of slag handling, butalso have serious inherent shortcomings limiting useful capacity of thefurnaces. Improvement over such prevailing methods of handling anddisposing of increasing tonnages of OSM or BOF slag in less time hasbecome critical in minimizing and avoiding production delays which mayaffect the entire mill, with tremendous economic ramifications.

It has been apparent for some time that the long standing and currentlyused multiple-step materials-handling systems for handling and removingsteel slag have serious inherent limitations which will penalize thefurnaces run when at the materially higher tonnage-shorter heat timesnow feasible.

For some time heretofore, blast furnace and other molten metal slagshave been granulated with water; but, granulation of steel slags bysimilar techniques involves different problems whereby such watergranulation of steel slag was found dangerous and/or inoperative. Thisis summarized in Canadian Pat. No. 562,523 on Method and Apparatus ForHandling Slag Resulting From Steel-Making Operations," issued to HarryV. Tomlinson on Aug. 26, 1958, from an application filed Mar. 17, 1963,and assigned on its face (60 percent) to the Harsco Corporation ofHarrisburg, Pennsylvania, a leader in the field of handling steel (andother) slag disposal for United States steel producers, said patentstating:

My invention, as a primary object, seeks to teach a practical method ofgranulating slag produced during various steelmaking processes by theintroduction of a slag while in a molten condition into water, both theslag and the water being controlled in accordance with the teachings ofthe invention. In this respect the invention should be contrasted withvarious heretofore known and/or suggested methods of granulating blastfurnace slag by the introduction of the same into a stream or bath ofwater. While it is true that the basic concept of granulating slags byintroducing the same into water is old, the present invention, in itsmost important aspect, is concerned with a particular method ofcontrolling the water and slag during the introduction of the latterinto the former whereby the basic process is rendered capable ofcommercial application in the treatment of steel-making slags."

It will be readily appreciated by those skilled in the art that slagsproduced in steel-making operations are tapped from the furnace at aconsiderably higher temperature than are blast furnace slags. Thisfactor creates an unusual problem in that the higher temperaturesteel-making slag tends to combine explosively with the water clue tothe extremely rapid generation of steam and liberation of hydrogen andcarbon monoxide gasses. Thus, methods heretofore known to be effectivein the granulation of blast furnace slags have been found to bedangerous and/or inoperative when applied to the treatment ofsteel-making slags.

The aforementioned Harsco Canadian patent seeks to successfully andsafely granulate steel slag on a practical commercial basis by pouringthe molten slag from an open hearth furnace into a bath of water in atank, with water fed into the tank below the water-bath surface and aslow as one-half way to the bottom of the tank to create a water currentin the bath at this level. Contrary to the objectives stated in theCanadian patent, the steel-slag system of the I-Iarsco patent issusceptible to explosion, and is dangerous (if not inoperative), asidefrom otherwise being impractical and unacceptable from the viewpoint ofreal-life steel mill operations, for many reasons. In any event,although Harsco is one of the largest handlers of steel slag in theUnited States, it does not use the I-Iarsco-Tomlinson Canadian patentsystem for steel slag, at least in the U.S. steel industry so far as canbe determined. U.S. steel producers and their slag contractors(including Harsco) continue to use such above-discussed batch-type,multistep, slag handling systems, utilizing slag pots with rail cars,vehicles or cranes, or highlifts with trucks and tractors, etc., inspite of the many shortcomings and problems of such prior systems.

Hence, removal of steel slag by multiple-step batch systems has been andis a bottleneck that prevents the maximum utilization of existing OSMand BOF open hearth and steelmaking furnaces, thus hindering realizationof tremendous economic savings and other advantages, including increaseof national defense steel production with existing equipment.

My aforementioned earlier copending applications disclose inventionsproviding new improved slag handling and removal systems which departfrom the materials-handling concepts of current and earlier steel slagsystems discussed above, thus avoiding their serious shortcomings andmaking it possible to achieve fast continuous handling and removal ofmolten steel slag from open hearth, BOF OR OSM and other steel furnaces.More particularly, inventions of my aforementioned earlier applicationsprovide new improved slag handling methods and apparatus whereby themolten slag from the steel making furnace is discharged to a granulatorwherein it is suddenly cooled and granulated by jets of water to formrelatively small particles which are then transported by continuousconveying means to a suitable reclamation and disposal area at adistance from the steel furnace building. Thus, large tonnages of steelslag produced in a large heat are disposed of in a very short time afterthe furnace is tapped, so that steel slag handling does not continue asa bottleneck preventing shorter heat times and optimum use of largecapacity OSM or BOF and open hearth furnaces.

The inventions of my aforementioned earlier copending applicationprovide water jet granulator methods and apparatus having a novelarrangement and mode of operation making it possible to handle largetonnages of molten steel slag in a short time period, without creatingexplosions, or other dangerous or otherwise undesirable workingconditions which the steel industry has heretofore encountered inattempting to granu- Iate steel slag with water. Hence, these inventionsincrease the safety of slag removal operations, thus furthering thediligent efforts of U.S. steel companies to continuously improve safeworking conditions in the mills, which is a matter of prime concern tothe U.S. steel industry.

It is a principal object of the present invention to provide a furtherimproved novel steel slag handling and removal system incorporatingsteel slag granulation inventions disclosed in my aforementioned earliercopending patent applications plus new improved means for hydraulictransport of the granulated slag and ferrous material directly to adistant disposal area for economical separation of reusable ferrousmaterial and disposal of nonferrous slag material. It is a relatedobject of this invention to provide such a new improved steel slaggranulation and hydraulic removal and transport system which is veryfast in operation, substantially reduces the high per ton cost ofcurrently used slag removal and metal recovery systems, greatlydecreases the cost of equipment per ton of slag removed compared toprior slag removal systems, and reduces serious and costly equipmentmaintenance problems currently encountered.

It is another principal object of the present invention to provide newimproved methods and apparatus for granulation of molten steel slag anddirect hydraulic transportation of the resultant granulated slag whichtake into account and balance pertinent factors such as: temperature andviscosity of steel slag discharged into the granulator; the quantity ofmolten steel slag, and sometimes steel, discharged per minute into thegranulator, especially at maximum rate; the angle of the chute (or othermeans) discharging the slag into the granulator; the size, shape andlocation of the granulator jet nozzles; the water input to thegranulator jets and water jet velocity (e.g., in fps.) and the rate ofwater input to slag input for a given time period (e.g., g.p.m. water totons/min. slag); the input water temperature for the granulator jets,and temperature of granulator water output; correlation of the foregoingand the hydraulic transport system construction and mode of operation,including minimum slurry velocity and surge load tolerance in relationto granulator operation based on variable slag loads on the granulator;and incorporation of suitable safeguards in the construction and mode ofoperation of the overall system.

It is another related principal object to provide a commerciallydesirable steel slag granulation and hydraulic transport system whichnot only safely, continuously, and rapidly granulates and removes largetonnages of molten steel slag, but also meets steel-mill operatingrequirements such as minimal water consumption, minimal steam, suitablecontrol of particle size for economical magnetic separation, readyadaptability to varying type steel furnace slags and varying tonnagedisposal rates, and trouble-free operation by semiskilled workers.

Other important objects and advantages of the present invention will beapparent from the following description thereof with reference to theaccompanying drawings, and from the claims appended hereto. In thedrawings:

FIG. 1 is a diagrammatic cross section of a steel-making furnace (ofopen hearth type, along a line through the tap spout) showing anembodiment of the steel slag handling and removal system of thisinvention, including a granulator for converting molten steel dischargedinto it, and a hydraulic system for conveying the granulated slag afterremoval of oversize pieces.

FIG. 2 is a top plan view of the steel slag granulator and relatedhydraulic slag transport apparatus shown in FIG. 1 (some parts in theupper part of FIG. 1 being omitted for clarity, and looking in thedirection of arrow 2 in FIG. 1

FIG. 3 is an end elevation view of the granulator and hydraulic slagtransport means shown in FIGS. 1 and 2 (looking to the right per arrow 3in FIG. I);

As will be apparent from comparing the drawings herein with those in myaforesaid earlier applications, Ser. No. 126,792; Ser. No. 428,519; Ser.No. 485,037 and Ser. No. 304,932, FIG. 1 herein is similar to sideelevation FIGS. 5 and 12 of my parent application Ser. No. 126,792 andlike FIGS. 2 and 9 in my copending applications Ser. No. 428,519 andSer. No. 485,037, and also FIG. 1 in Ser. No. 304,932 (but looking atthe opposite side of the steel slag granulator system in sideelevation).

In the following description, like numerals are used for like partsthroughout. To facilitate and abbreviate the description herein, partsof the new improved system shown in FIGS. l-3 hereof which are the sameas in the embodiment of FIGS. 4-13 of my parent application Ser. No.126,792, and in like FIGS. 1-11 of c-i-p applications Ser. No. 428,519and Ser. No.

485,037, are identified by like numerals as in said figures of myaforesaid earlier parent applications. Further, modified parts areidentified to the extent feasible with like numerals as correspondingparts of the arrangement in said figures of my aforesaid applicationsSer. Nos. 126,792; 428,519 and 485,037 plus the subscript k."

R; 'erring to drawing FIG. 1, the numeral 20 generally indicates atypical open hearth steel-making furnace within a building containing acharging floor 24, with an area 26, called the kitchen," below thecharging floor. Details of the open hearth furnaces 20 and relatedequipment within the open hearth furnace building are not shown ordescribed except to the extent helpful for illustrative discussion ofthe present invention. For more details see my aforementioned earliercopending applications, and also see chapter of The Making, Shaping andTreating of Steel, 7th Edition, United States Steel Corporation (1957),and items in the bibliography on pages 332-333 thereof.

The front wall 30 of the open hearth furnace contains a plurality ofcharging openings 39 (usually five or seven in number); and each ofthese is covered by a vertically movable charging door (not shown). In atypical open hearth furnace operation, during the steel-makingoperation, part of the slag overlying the steel bath in the furnace 20is discharged through a notch or trough cut in the refractory of thefront bank of the furnace at the center door opening 39. This frontflush slag 64 passes through a spillway 66 in the charging floor 24, andnormally into a pit 68 below the furnace, which is filled with dirt ordebris to form a hill 72, whereby the hot front-flush slag dischargedthrough the opening 66 pours onto slag grade 72 and flows down towardsthe pit side of the furnace as amplified in my above-identified earlierapplications. The front flushing of slag may continue for l to l-% hoursin good operating practice with a 350-ton furnace; but, at times, slagis front flushed at a very high rate, estimated as high as 4 tons perminute.

Referring especially to FIGS. 1 and 2, which show the system of thisinvention with an open hearth steel-making furnace for illustration, themolten steel slag 64 is discharged into an inclined trough-shapedfront-flush slag runner or chute 78k, which extends through an aperturein vertical wall 27 and is suspended so as to be movable to displace theend of chute 78k from below the spillway 66 (as hereinafter amplified).The molten slag 64 spills from the lower end of the runner or chute 78kinto one end of a granulator generally indicated at 82k, which islocated at yard level in the kitchen 26, and is more fully describedbelow.

Referring especially to FIGS. 1 and 2, the slag granulator 82k comprisesa large rectangular tank which is somewhat boat-shaped as shown. Thegranulator 82k includes a tank made up of a framework plus ahorizontally disposed rectangular bottom plate 106, a sloping bottomrectangular plate 108k, a pair of like vertical plate sidewalls 110having a configuration as shown in FIG. 1, and a rectangular end wall112 (towards the furnace). The aforementioned components are welded, orotherwise suitably secured together to form a watertight tank ofboatlike shape for granulator 82k in a manner known in the art. [For amore detailed description of the granulator tank, see my aforementionedapplications Ser. Nos. l26,792;428,5l9; and 485,037.]

One tank sidewall 110 (the upper shown in FIG. 2) is provided with arectangular cutout 114 of suitable size to provide a weir 116 foroverflow of water in the tank, indicated at 117. The water flows fromthe tank of granulator 82k into a rectangular-shaped water discharge box119, from which it is in turn carried away through a discharge pipe 121.[For a more detailed description of these components of granulator 82k,see drawings and discussion of like-numbered components in myaforementioned applications Ser. No. 126,792, Ser. No. 428,519 and Ser.No. 485,037.] In this system, the pipeline 121 extends to an auxiliarytank 210 having a bottom 212 and four rectangular sidewalls 214, with anopen top, for purposes hereafter amplified.

A suitable arrangement is provided at the end of the granulator 82k tosupport the lower end of the slag feed chute 78k which overhangs thetank end 112 of the granulator 81k (as more fully discussed below). Theend wall 112 of granulator 81k is provided with a pair of rectangularapertures that receive the forward ends of nozzles 130, which are shownand described in detail in my earlier aforementioned applications; seeFIGS. 8-20 of Ser. No. 126,792 and FIGS. 5-7 of Ser. No. 428,519 andSer. No. 485,037 and related description incorporated by referenceherein. Each of the. nozzles has a configuration which forms arectangular passageway so that water is ejectedfrom the nozzle 130 in aflat wide jetstream. Each nozzle 130 is mounted on the granulator 81k byany suitable means (not shown for clearer illustration in the drawings),with the forward ends of the nozzle 130 extending through rectangularapertures in the tank end wall 112 of granulator 81k.

Water is fed through the nozzles 130 from supply conduits 131k undersubstantial pressure by suitable commercially available means, e.g.,pump 216, whereby the water is expelled from the rectangular openings ofeach of nozzles 130 in two flat jetstreams, one over the other. The hotslag which spills into the end of granulator 82k from the chute 78kintercepts these flat jetstreams of water from nozzles 130, thus causingthe slag to be rapidly chilled and granulated into particles of solidmetal, solid ferrous ore, nonferrous slag and gangue. This granulationof the molten steel slag is achieved by a combination of mechanicaldisruption and chilling of the molten steel slag discharged intogranulator 82k by the water jetstreams from nozzles 130, particularlythe upper nozzle.

The granulator 82k is provided with an endless rake-type flightconveyorgenerally indicated by the numeral 132. [Conveyor 132 is shownespecially in FIGS. 5 and 6 of my aforementioned application Ser. No.126,792 and in FIGS. 3 and 4 of my applications Ser. No. 428,519 andSer. No. 485,037 and is fully described in the specifications thereof,which disclo sure is incorporated herein by reference] The conveyor 132includes three endless link chains extending over each of the three setsof aligned sprockets and rollers mounted on the upper ends of granulatortank sidewalls 110, with part of each chain 145 being suspended near thebottom plates 106 and 108k of the granulator 82k, as illustrated inFIGS. 1 and 2. A series of rectangular steel slights 145 are secured toportions of three endless chains 145 by suitable means, thus providing aplurality of drag flights extending substantially across the width ofthe tank granulator 82k at small spaced intervals.

The lower sections of the chain flight conveyor 132 are located near thetank bottom plates 106 and 108k so that the flights 146 will rake thegranulated slag and metal in granulator 82k to the upper prow end ofsloping bottom plate 108k, adjacent roller shaft 144, with edges of theflights 146 slightly clearing the bottom tank plate 106.

The flight chain conveyor 132 is driven in the direction indicated bythe arrows in FIG. 1 by a suitable variable speed motor and driveillustrated at 150 (and more fully shown and described in myaforementioned applications Ser. No. 126,792, Ser. No. 428,519 and Ser.No. 485,037).

It will be noted that the slag can be discharged from the slag chute 78into the granulator 82k through the flights 146 of the rake conveyor132, whereby continuous rake conveyor operation does not interfere withthe feeding of the steel slag into granulator 82k, even during periodsof maximum steel slag feed when the slag may be thrown forward from theend of chute 78 as it spills into granulator 82k.

To avoid having steam generated within the granulator tank 82k pas passoff into the furnace building kitchen" 26 in objectionable quantities,the granulator 82k is preferably also provided with a suitable steelhood generally indicated at k in FIGS. 1 and 2. [Illustrated steam hood180k is of like construction as hood 180h shown and described in myaforementioned application Ser. No. 304,932 to which reference is madefor further details] Referring back particularly to FIG. I, the chute78k for feeding granulator 82k is movable by hoist means generallyindicated at 80k for installation of the system for an open hearthfurnace, for reasons amplified in applications Ser. No. 126,792 and428,519.

As shown particularly in FIG. 2, the slag chute 78k comprises anelongated runner and boot section 78k and an enlarged head end 78k" witha configuration as illustrated. The chute 78k is made of cast steel,with a radius on all angles to facilitate free flow of the slag in thechute which may also be lined with a suitable refractory material ifdesired. The upper end of chute 78k is provided with a pair of lugs 99kto which are attached a pair of cables or chains 87k, with the lower endof chute 78k being pivotally mounted on or adjacent granulator end wall120 so that chute 78k may be pivoted upward to dotted line positionillustrated in FIG. 1 and dropped to full line illustrated position byrotation of pulley 89k through any suitable known means (which per se isnot a feature of this invention).

As will be apparent from FIGS. 1 and 2, in the illustrated open hearthfurnace installation of this new system, the head end 78k of chute 78kextends through aperture 25 in the upper part of the vertical wall 27which separates the kitchen 26 from the pit 68 below the furnace 20.Thus, when the slag chute 78k is in lowered position shown in solid linein FIG. 1, the steel slag 64 flushed from furnace 20 is dischargedthrough the spillway 66 into the head end 78k" of chute 78k, and thenflows down chute 78k, which is at a suitable angle, i.e., about 35 fromhorizontal, and spills from the boot end 78k into the granulator 81kwhere it is converted to granular particles of slag and metal, aspreviously explained. If, for some reason, it is desired not to use theslag granulator 82k, the head end 78k" of the chute 78k is raised byrotation of pulley 89k, and cable 87k to the dotted line position inFIG. 1 whereby chute head end 78k is removed from the path of the moltenslag by spilling through spillway 66, then the molten slag (or steel) 64is promptly diverted from the granulator 82k to the ground for removalby current practices described above, when necessary or desirable; e.g.,in the case of an open hearth furnace reaction" or break out there wouldbe sudden increase of load on the granulator 82 which could create adangerous condition if the surge of molten slag (and/or steel) were notdiverted.

Suitable hoist means such as diagrammatically indicated at 80k arecommercially available, and arrangements for employing them in a systemaccording to FIGS. 1 and 2 will be apparent to those skilled in the artin light of the disclosure herein and in my copending applications Ser.No. 126,792, Ser. No. 428,519 and Ser. No. 485,037.

A preferred embodiment for granulation of open hearth steel furnacefront-flush slag according to the present invention using a preferredmovable chute arrangement for transferring molten slag to a granulator(like 82k) in the kitchen 26 away from below the charging floor spillway66 and promptly diverting the molten slag from the granulator to belowthe furnace, when desired, is disclosed in my aforesaid copendingapplication Ser. No. 304,932 on Steel Slag Handling System, whichdisclosure is incorporated herein by reference as though fully set forthherein. Hence, further detailed showing and discussion thereof isbelieved unnecessary, especially since the particular details of thesechute displacement means are not per se a part of the present invention,and may in fact be omitted in using the present invention in granulationand hydraulic transport of BOF or OSM and electric steel slags.

For convenience, the granulation system of FIGS. 1-3 may be consideredas having three mutually perpendicular reference axes, indicated at x, yand z in FIGS. 1-3. Thus, in the illustrated embodiment the length ofgranulator 82k extends in the direction of horizontal axis x withsidewall and other components extending in the direction of verticalaxis y, and with other components extending transversely to thegranulators longitudinal axis x as indicated at 2. Referring to FIGS.5-7 of my aforementioned applications Ser. Nos. b

428,519 and 458,037 and FIGS. 8-10 in Ser. No. 126,792, each water jetnozzle is provided with a flat rectangular opening 13511 so that a flatwide water jetstream is emitted horizontally from nozzle 130 in thedirection of axis x of granulator 82k.

By way of example, water ejection nozzles 130, shown in said Figures ofmy earlier applications, may have a rectangular jet aperture 1351: ofabout 14 inches by three-sights inch in cross section, for a granulator82k about 32%-feet long overall, with flat bottom 106 being about 20feet long, about 5 feet high at the jet end and 7r-feet high at the prowend, and about 5 /-feet wide; and the upper and lower nozzles 130 beingrespectively located about 1 foot and l%-feet from the upper edge of thetank end wall 112. It has been found that the width of the rectangularwater jet aperture of each nozzle 130, in the direction of granulatorstransverse axis 2, should preferably exceed by at least 10 percent thewidth between the inside of the sidewalls 211k of the end portion 78k ofthe slag chute 78k, when the centerline of end portion 78k of the slagchute overlies the centerline of each water jet nozzle 130, asillustrated. If, however, the chute nozzles do not have theircenterlines so aligned, then the width of said jet nozzle opening andthe width of end portion 78k of slag chute 78 between walls 211k atgranulator 82k should be such that each slag chute sidewall 211k islocated in transverse direction 2 so that the adjacent sidewall ofnozzle 130 forming the water jet aperture is disposed outside or beyondthe respective chute wall 211k a distance equal to at least 5 percent ofthe chute width. Slag chute end 78k should not extend any substantialextent in the direction of the transverse horizontal z axis, to avoidfeeding molten slag with any substantial trajectory in the direction ofaxis z transverse to the water jetstream injected in direction of axisx; that is the slag chute 78k should extend in the direction of thelongitudinal axis x when slag is being poured into the granulator 82k.Also, it is found desirable to make the slag chute end portion 78kfeeding the granulator 82k with substantially parallel sidewalls 211kextending for a sufficient length in the direction of the longitudinalreference axis x to assure a proper molten slag trajectory withreference to the water jetstreams from nozzles 130. (That is, it ispreferable not to use a slag chute whose end portions adjacentgranulator end wall 112 have nonparallel sidewalls extending in thedirection of transverse reference axis z.) However, the jet nozzles 130may be tilted slightly up or down in the direction of vertical referenceaxis y, so as to be at a slight angle to horizontal reference axis x.

Water is fed to nozzles 130, via conduits 131k, at sufiicient pressure,e.g., 35-60 p.s.i., and in sufficient amount, to produce substantiallyinstantaneous solidification and granulation of the slag into metal andnonmetal particles of sizes usually running less than one-half inch indimension, as hereafter amplified.

Water or a liquid of comparable characteristics must be used as theliquid for the jet stream and cooling medium to granulate molten steelslag in granulator 82k according to the system herein disclosed.However, because of its availability in large quantity at low cost,water is the only presently known liquid which is commercially usablefor the steel slag granulation system of this invention. [The termwater," however, contemplates aqueous solutions with additives such asto change boiling point temperature or vaporization of the coolingmedium, or the like] Referring now particularly to the hydraulicgranulated slag slurry transporting arrangement generally indicated at216 in FIGS. 1 and 2, the sloping bottom plate 108k of granulator 82k ismodified to incorporate a section 218 having a plurality of apertures220 which have a preselected maximum dimension of between '74 inch to 2inches. Instead of a perforated plate section 218, it is possible tosubstitute at 218 a grating having a preselected maximum aperturedimension of A inch to 2 inches. The perforated or grating section 218overlies the auxiliary tank 211) so that minus V4 inch to 2 inchesgranulated slag (and metal) particles and water moved up the slopingbottom wall 108k of granulator 82k beyond the perforated bottom section218 (i.e., to the left of perforated section 218 as shown in FIG. 1),and above the auxiliary tank 210. The sloping screen 224 extendssufficiently beyond the prow end of granulator 82k and rake conveyorpulley 144, as illustrated particularly in FIGS. 1 and 2, so thatgranulated slag (and water) discharged from the prow end" of thegranulator 82k will fall onto screen 224. Screen 224 is provided withmesh, grating or screen having a maximum aperture size which limits thesize of solids falling into the auxiliary tank 210 to a preselecteddimension, and thereby prevents oversize solids from entering thehydraulic granulated slag slurry transport system 216; e.g., in asuitable embodiment the screen 224 may have a mesh or aperture size ofplus 2 inches. Screen 224 is mounted below granulator bottom slopingwall 108k and above auxiliary tank 210 by any suitable means, in amanner which will be apparent to those skilled in the art from thedisclosure herein; e.g., the screen 224 may be mounted by means of anangle 226 or the like secured to the underside of the bottom granulatorsloping wall 108k plus a plurality of posts 228, 230 and 232 extendingbetween the frame 225 of screen 224 and the side walls 212, 214, 215,and 217 of auxiliary tank 210. As shown particularly in FIGS. 2 and 3,the lower end of slanted screen 224 extends over the sidewall 212 ofauxiliary tank 210 and the adjacently disposed sidewall of a movabletote box" 234. Thus, solids in excess of the mesh size of screen 224e.g., over 2 inches) discharged from the prow end of the granulator 82kfall by gravity down screen 224 into the tote box 234, whereas slurrycontaining solids less than the mesh size of screen 224 will fall intothe auxiliary tank 210 for subsequent removal by the hydraulicgranulated slag slurry transport system indicated generally at 216. Thetote box 234 is removed for emptying, and replaced, as necessitated byaccumulated oversize solids.

If desired, a suitable commercially available vibrator device may beprovided for agitating 224, in a manner which will be apparent to thoseskilled in the art in the light of the disclosure herein. Such a screenvibrator device increases the assurance of transfer of oversize solidsfrom the screen 224 to the tote box 234. However, a vibrator isunnecessary in many instances, since the force of gravity is adequate tocause most of the oversize solids to roll down screen 224 into the totebox 234, and the operator may check an clear the screen after completionof a slag run.

It is noted that use of apertured or grating section 218-in the bottomof granulator wall 107k is preferable because it removes a largeproportion of the granulated slag and water slurry and minimizesexcessive throwing" of slurry from the prow end of the granulator byrake conveyor flights 146.

Referring especially to the hydraulic slag slurry transport meansindicated generally at 216, a pipe 236 is connected to the lowermostportion of one of sidewalls 217 of auxiliary tank 210 and to the input238 of a suitable commercially available centrifugal pump 240 which isdriven by a suitable power source, such as an electric motor speedcontrol device shown at 242 (see particularly FIGS. 1 and 3). The output244 of pump 240 is connected to a discharge line 246, which preferablyis provided (in an accessible region near the granulator 82k) with asuitable commercially available check valve 248 and shutofi valve 250.The discharge conduit 246 is suspended from parts of the furnacebuilding by suitable means such as hangers indicated schematically at252, and extends outside the furnace building to a suitable disposalpoint at a distance from the building e.g., 1,700 feet (such pumpingextension not shown in detail as that would be apparent to those skilledin the art in the light of the disclosure herein). In some installationsthe lower outlet end 247 of the discharge pipe 246 may be disposed belowthe level of the pump 240 to create a siphon efiect, thereby decreasingthe power requirements of the drive motor 242 of pump 240, however, thisis not essential, and in fact involves a countereconomic factor becausesiphoning requires that the sections making up discharge pipe 246 andrelated couplings be airtight, which is not required if such siphoneffect is not sought.

Referring particularly to FIGS. 1-3 in the illustrated embodiment,centrifugal pump 240 is disposed a distance equal to one floor levelbelow the yard or floor level on which granulator 82k and auxiliary tank210 are disposed. This is desirable to provide a suction head for inlet238 of pump 240, which preferably should be about 10 feet of head tominimize inefficiency, sealing or related problems in operation ofcentrifugal pump 240 when the granulated slag slurry fed through pumpinput 238 via conduit 236 from granulator 82k and auxiliary tank 210approaches or reaches boiling temperature of 2l2, as when granulator 82kis loaded at a high rate of tons of slag (and metal) per minute, asamplified below. However, the slag slurry system 216 may be operatedwith the pump 240 disposed at the same yard or floor level as granulator82k and auxiliary tank 210, e.g., at the location indicated at 241 inFIG. 1. Some steel furnace plants are so constructed without asub-basement as shown in FIGS. 1 and 3, so that it may not be possibleto lower the pump 240 with respect to auxiliary tank 210 to such extent.However, it is desirable to produce such input head as is feasiblebetween the outlet of tank 210 and inlet 238 of pump 240, as by puttingpump 240 in a small well or by raising the granulator 82k and auxiliarytank 210 on a platform (the latter may be desirable with some steelfurnaces for other reasons, such as a shorter slag chute 78k feedinggranulator 82k to minimize viscosity problems for certain types of steelslags).

Referring back particularly to FIGS. 1 and 3, the cutout 1 14 in thesidewall (upper in FIG. 3) and the weir edge 116 determine the waterlevel 117 in granulator 81k and thus the level of water in the weiroutlet box 119, as described earlier (and as shown and explained ingreater detail in my aforementioned applications Ser. No. l26,792, Ser.No. 428,5l9, Ser. No. 485,037, and Ser. No. 304,932). This normallyestablishes a like water level indicated at 117' within auxiliary tank210, to which water is transferred from granulator 82k via weir box 119conduit 121. When the pump 240 is operating to remove the granulatedslag (and metal) water slurry from auxiliary tank 210, it may causewater level 117 within auxiliary tank 210 to fall, as when the pumpingrate of pump 240 exceeds the volumetric rate of input and output ofwater alone or with slag in granulator 82k and tank 210. Accordingly,auxiliary tank 210 is provided with a suitable commercially availablefloat or other flow control device generally indicated at 254, plusrelated piping and water source. Such flow control device 254 contains avalve operated in response to the change in water level 1 17 withinauxiliary tank 210 cause addition of water to auxiliary tank 210,whereafter flow control device 254 cuts off further supply of water totank 210 when the water level 117' within auxiliary tank 210 is at aproper level within preestablished tolerances. Since the particularfloat or other flow control device 254 is not per se a part of thisinvention, and various suitable commercial types are available and maybe used in a manner apparent to those skilled in the art in light of thedisclosure herein, further description of flow control 254 is deemedunnecessary.

A runoff pipe 256 is preferably provided slightly below the top of theauxiliary tank communicating with an aperture in tank wall 217, wherebyif excessive water or granulated slag slurry if fed into auxiliary tank210, water overflows through runoff pipe 256 which is connected to anexisting sewer or other water disposal means. The heavier granulatedslag and metal particles settle by gravity within auxiliary tank 210fairly rapidly so that the runoff through overflow pipe 256 is waterwithout substantial solids.

Referring particularly to FIGS. 2 and 3, in some furnace installationsthe sewer level or other waste water discharge arrangements may be ofhigher elevation than granulator 82k and auxiliary tank 210 whereby itis desirable to provide an additional smaller centrifugal pump 258driven by suitable means such as motor 260. This second pump 258 may beturned on manually, or by suitable automatic means, to dischargeexcessive water from auxiliary tank 210 either in conjunction withrunofi pipe 256, or without it (as where the sewage disposal point isabove the tank so that overflow runoff pipe 256 cannot be used. It isnoted that when the lower end 247 of discharge conduit 246 is extendedto a level below hydraulic pump 240 for utilizing the above-discussedsiphon effect to minimize power requirements for pump motor 242, it isnecessary to take into account possible backflow of the volume of wateror granulated slag slurry contained within that part of the elongateddischarge conduit 246 which is above the level of the auxiliary tank 210when the siphon is broken; thus a suitable runoff pipe arrangement 256and/or auxiliary pump 258 to handle backflow through discharge conduit246, pump 238, and input conduit 236 to tank 210, in addition to checkvalve 248 and shutoff valve 250 may be desirable.

Referring back especially to FIG. 2, the granulator 82k is alsopreferably provided with a manifold 262 having a series of spray heads264 and supplied with water from a conduit 266 connected to a suitablesource. Preferably, flow of water through 266, 262, 264 is governed by athermostat control arrangement generally indicated at 267. This includesa thermostat switch device 268 of suitable commercially available typeinserted into weir box 119 below the level of weir 116, with thermostatswitch 268 operating a suitable commercially available spring biasedsolenoid control valve such as schematically shown at 270 in watersupply conduit 266. The arrangement is set so that when the thermostatelement of thermostat switch 268 is affected by a granulated slurrytemperature in granulator 82k and weir box 119 approaching apredetermined differential from boiling, 212 F., e.g., 185 F., theswitch portion 269 will close so that current in circuit 271 from sourceV will energize and cause normally closed solenoid operated valve 270 toopen. This permits flow of water through valve opening 273 and conduit266 into manifold 262 from which it is sprayed into granulator 82kthrough nozzles 264, thereby cutting the temperature of the granulatedslag slurry water bath in granulator 82k. While water may be added togranulator 82k by analogous thermostatically controlled means using oneor more pipes in lieu of spray nozzles 264, the use of spray nozzles hasthe advantage, in some instances, of more effectively depressing steamover granulator 82k, which is desirable from an operating viewpoint.

In addition, a similar thermostatic control arrangement is preferablyprovided for auxiliary tank 210, as generally illustrated at 276 in FIG.2 This includes a thermostat switch 278 inserted through sidewall 215 ofauxiliary tank 210 at an appropriate point, below the normal range ofwater level 1 17' as controlled by flow device 254; and thermostatswitch 272 controls a suitable commercially available solenoid operatedvalve schematically shown at 280 in a water input conduit 282 connectedto the interior of tank 210 through an aperture in tank wall 215. Thus,thermostat switch 278 may be set so that when the water and slag slurryin tank 210 is within a predetermined temperature range of boiling, 212F., e.g., 185 F., it will energize and cause normally closed solenoidvalves 280 to operate displacing valve opening 281 in water line withconduit 282 so that water is fed into the auxiliary tank 210 from asuitable source to lower the temperature of the water in auxiliary tank210.

Use of one, and preferably both of the thermostatic control systems 267and 276 makes it possible to maintain the temperature of water and slagslurry fed from auxiliary tank 210 to centrifugal pump 240 throughconduit 236 at a temperature sufficiently below boiling 212 F. tomaximize efficient operation of the centrifugal pump 240 (in balancewith other aspects of the system as herein discussed).

From operation of a steel-slag granulation system such as disclosedherein, it has been found that the steel-slag granulation systemaccording to this invention should preferably be operated according tothe following conditions:

1. Water should be supplied to appropriately sized granulator nozzle(s)130 via associated water conduit(s) 131k in such quantity that the flatjetstream of water is injected into granulator 82k from nozzle(s) 130 ata jet velocity in feet per second (f.p.s.) and in gallons per minute(g.p.m.) varying in relation to the rate at which molten steel furnaceslag is poured into granulator 82k to intercept the water jetstream(s),as follows: (a) For a molten slag input rate of up to about 2 tons perminute, at least one flat water jetstrearn at a jet velocity of at leastabout 25.0 fps, and at least about 400 g.p.m., (b) For a molten slaginput rate of 2 tons to about 4 tons per minute, at least one fiat waterjetstream at a jet velocity of at least about 30 to 36.5 f.p.s., and atleast about 500600 g.p.m. (c) For a molten slag input rate of 4 to about7 tons per minute, inject at least about l,200l,800 g.p.m., either bytwo flat water jetstreams through two nozzles, one over the other, eachwater stream having a jet velocity of at least about -b 36.5 to 55 fps;or through one flat water jetstream via one nozzle with a jet velocityof at least about 73 to fps. (d) For a molten slag input rate of over 7tons per minute, e.g., 7-8, inject at least l,8002,000 g.p.m., either bytwo flat water jetstreams through two nozzles, one over the other, eachwater stream having a jet velocity of at least 55 to 61 fps, or throughone flat water jetstream via one nozzle with ajet velocity of at leastabout I 10 to 122 fps.

2. Water should be introduced to granulator 82k at a quantitative ratein gallons per minute varying in relation to the rate at which moltensteel furnace slag is poured into the granulator 82k as follows: (a)Water should be introduced into granulator 82k at the slag input end(adjacent wall 112) at an average rate of at least about 400 g.p.m., perton of steel slag per minute poured into the granulator. (b) However,water should preferably be introduced at the slag input end of thegranulator 82k at an average rate of about 900-1 ,350 g.p.m., per ton ofsteel slag per minute poured into the granulator. (c) And, it is best touse at least about 1,350-1 ,600 g.p.m., per ton of steel slag per minutepoured into the granulator to avoid objectionable vaporization andformulation of steam. The input water preferably should be a typicalwater main temperature (e.g., 60 F. to 70 F.); however, furance-coolingwater or other plant-used water may be employed, but its temperaturepreferably should not exceed 100 F.

3. It is preferable that the amount of water per paragraph 2 beintroduced into granulator 82k by means of the jet nozzles in suchquantitative g.p.m., rates according to varying molten steel slagtonnage input rates. However, with the suggested embodiment, size of jetnozzles 130 is such that the desired water jet velocities and g.p.m.,per parts (a), (b), (c) and (d) of paragraph 1 above frequently can beachieved with a lower quantity of water through the nozzle(s) 130 thanrequired to meet the conditions of part (a), (b) or (c) of paragraph 2.In such event, it is possible to introduce the requisite water perparagraph 1 through the jet nozzle(s) 130 to achieve at least the waterjet velocities and g.p.m., set forth in paragraph 1 above, and tointroduce the remainder of the water per paragraph 2 by other means;e.g., a water pipe of suitable size may be secured to end wall 112 ofgranulator 82k below the lowest nozzle 130, at point 220 or 222 in FIG.1, to supply additional water to granulator 82k by conduit from asuitable source. However, the safest and best approach is to introduceall water requirements per paragraph 2 into granulator 82k through thewater jet nozzle(s) 130. This increases the effectiveness of the waterjets for breaking down the molten steel slag into small particles toachieve more rapid and more efficient slag cooling and granulation, andhelps control resultant granulated slag particles for better magneticseparation and also efficient hydraulic slurry transportation asamplified below.

4. In light of the foregoing, good results can be achieved by operatingthe granulator system of this invention using two flat jetstreams ofwater injected horizontally into granulator 82k through two likesizenozzles 130, one over the other, according to the following: (a) Formolten slag input of up to about 2 tons per minute, inject two waterstreams with jet velocity of about 36.5 to 61 f.p.s., and about1,200-2,000 g.p.m., through both jets. (b) For a molten slag input rateof 2 to about 4 tons per minute, inject two water jetstreams at avelocity of at least 61 to %f.p.s., and about 2,000-4,000 g.p.m.,through both jets. (c) For (slag input rate of 4 to about 7 tons perminute, inject two water jet streams at a velocity of at least about 91to 146 f.p.s., and about 3,000-5,000 g.p.m., through both nozzles.

5. Granulation of the molten steel slag is generally largelyaccomplished by the flat water jet stream from the upper nozzle 130,with the lower water jet stream from lower nozzle 130 supplementing theupper jet stream and also providing a safeguard against malfunction ofthe upper water jet while molten steel slag is being poured. Thus, moreeffective granulation of the molten steel slag may be achieved byinjecting 3/5 to 94 (60-75 percent), and preferably (66.6 percent), ofavailable water through the upper of two likesize nozzles 130 (14 inchesX inches opening, one over the other, aligned), and injecting thebalance of the water through the lower nozzle. Thus, in light of theforegoing, good results can be achieved according to the following: (a)For a molten slag input rate of up to about 2 tons per minute and usingwater available at about 1,200-2,000 g.p.m., inject about 800-1 ,350g.p.m. as) through the upper nozzle 130 at about 49 to 82 f.p.s., andabout 400-640 g.p.m. (91;) through the lower nozzle 130 at about 25 to39.5 f.p.s. (b) For a molten slag input rate of 2 to about 4 tons perminute and using water available at about 2,0004,000 g.p.m., injectabout 1,350-2,700 g.p.m. through the upper nozzle 130 at about 82 to 164f.p.s., and about 650-1,300 g.p.m. (16) through the lower nozzle atabout 39.5 to 79 fps. For a molten slag input rate of 4 to about 7 tonsper minute and using water available at 3,0005,000 g.p.m., inject about2,000-3,350 g.p.m. (36) through the upper nozzle 130 at about 122 to 202f.p.s., and about 1,000l,650 g.p.m. 16) through the lower nozzle at avelocity of at least about 61 to 101 f.p.s.

Operation of granulator 82k per the foregoing, especially per theconditions of paragraphs 4 and 5, provides resultant granulated steelslag of desirable particle size for efficient magnetic separation offerrous material, and efficient hydraulic transportation per discussionbelow.

The water may be supplied to one or both nozzles 130 through each ofconduits 131k by conventional pump means at suitable pressure and insuitable quantity to achieve the desired nozzle jetstream velocity andg.p.m., input per paragraph l above, the desired g.p.m., water input perparagraph 2 above, or the preferred jet velocities and g.p.m., perparagraph 4 or paragraph 5 above, according to varying rate of steelslag feed to the granulator with different size steel furnaces, in amanner which will be apparent to those skilled in the art in light ofthe disclosure herein and using known scientific and engineeringinformation.

By way of example, referring to operating conditions per paragraph 4above, with like nozzles 130 of granulator 82 having a rectangular jetaperture 135k or about 14 inches by inch in cross section, and a 4%-inch 1D section at 143b connected to conduit 131, water supplied at 35p.s.i., to each nozzle 130 may be injected into the granulator 82 atabout 68 f.p.s., and about 1,100 g.p.m., from each nozzle, and thus2,200 g.p.m., from both, according to the suggested operating conditionsof paragraph 4 above. As another example, if granulator 82 has largernozzles 130 having a rectangular aperture 13% of 22 inches by inch incross section (e.g., for use with a slag chute 78k having a width of 20inches) with a 4% -inch 1D section at l43b connected to conduit 131,water supplied at 35 p.s.i., may be injected into the granulator 82 atabout 75.5 f.p.s., and about 1,950 g.p.m., from each nozzle,

and thus 3,900 g.p.m., from both, according to suggested operatingconditions of paragraph 4 above.

Referring to paragraph numbered 5 above, the thickness of one or bothnozzles may be modified to analogously use more than half of availablewater in the jetstream from the upper nozzle and less than half in thelower jetstream. Thus, the opening 132b of upper nozzle 130 may have athickness (in direction of axis y greater than the thickness of openingl32b of lower nozzle 130, both the upper and lower nozzles having anopening 132k with' like width in direction of reference axis z. Forexample, the upper nozzle 130 may have an opening 132!) of 14 inches by9/16 inch while the lower nozzle 1321) has an opening of 14 inches byinch. Thus, by way of example, for a molten slag input of up to 2 tonsper minute and using 2,000 g.p.m., available water, 1,200 g.p.m., (60percent would be injected through the top nozzle at 49 f.p.s., and 800g.p.m., (40 percent through the lower nozzle at 49 fps.

Referring again more particularly to the hydraulic granulated slagslurry transport arrangement generally indicated at 216, this system 216must be constructed and operated in correlation with the granulation ofsteel slag in granulator 82k. For one thing, the average rate of outputof water and granulated slag slurry from granulator 81k mustsubstantially equal the average rate of input into granulator 82k ofwater via jets 130 (and otherwise) plus slag, subject to variations ofwater input into auxiliary tank 210 per flow control 254, overflow ofexcess water via runoff pipe 256, etc. as discussed above.

It has been found that the minimum velocity in discharge conduit 246 forgranulated steel slag discharged from granulator 82k is about 17 feetper second. it has also been found that up to about 17 percent solids towater is a suitable granulated slag to water ratio for slurrytransported through the system subject to 50 percent surge increase, andthe pump 240 should be able to accommodate same. It has also been foundpreferable to control the temperature of the granulated slag slurryauxiliary tank 210 so that it is fed to the inlet 238 of pump 240 viaintake conduit 236 at a maximum temperature of about F., but, thistemperature may be increased to boiling especially if the input pressurehead on pump input 238 is increased, as by a static head in conduit 236of 10 to 18 foot.

In typical steel slag granulation with operation of granulator 82kaccording to the foregoing discussed conditions, most of the particlesizes are below 65 mesh, with a small percentage of +65 mesh to minus$41 inch, and some inch to 2 inches. This is well handled by thehydraulic slag system 216 as discussed herein.

By way of example, a satisfactory installation of a hydraulic granulatedslag transport system 216 in conjunction with granulator 82k may beoperated as described herein with good results using a commerciallyavailable 3,500 g.p.m., 10-inch Aamsco-Nagle or Morris Dredgecentrifugal pump capable of handling particles of +2 inches to 4 inchesin size, and up to 3,100 gallons of water per minute plus up to 4 tonsof slag per minute, using 12-inch diameter input pipe 236 and a 10inchdiameter discharge pipe 246, 1,700 feet in length. The system describedmay be operated with an input of 1,800 g.p.m., of water through bothnozzles 130 providing two horizontal jetstreams having a jet velocity of55 f.p.s., at a slag tonnage input rate varying up to 4 tons per minute,and generally averaging 1 to 2 tons per minute. In addition to the 1,800g.p.m., of water introduced into granulator 82k through nozzles 130,makeup water is also introduced at the rate of 800 to 1,350 gallons toauxiliary tank 210 so as not to starve" the input to pump 240. The pumpis driven by suitable variable drive 242 to provide some adjustment forvarying g.p.m., water rate and slag content in accordance with operationof the granulator 82k at varying water and slag input rates.

As will be apparent, the velocity of the water and granulated slagslurry in the discharge pipe 246 will vary according to such factors as(a) variation in diameter of discharge pipe 246, and/or (b) variation involumetric rate of water and/or slag slurry through the system, and/or(c) variation in head on pump 240, e.g., due to difference in elevationbetween different points of the discharge pipe, and/or (d) pressurelosses due to length of discharge pipe 246. Accordingly, as will beapparent to those skilled in the art in light of the disclosure herein,the hydraulic transportation system 216 and its components must beconstructed and operated in correlation with operation of slaggranulator 82k consistent with the abovediscussed parameters for bothslag granulator 82k and hydraulic slag slurry transport system 216.

it is noted that in operating granulator 82k and hydraulic system 216,the level 117 of the water and slag accumulating in the tank ofgranulator 82k is maintained below the lowermost water jetstream fromeither or both of nozzles 130 so that molten slag intercepts at leastthe upper jetstream above the water level 117 in granulator 82k. It isalso noted the rake conveyor 132 agitates the bath and slag ingranulator 82k, displaces slag away from nozzles 130 to prevent buildupin the region of the nozzles and provides other advantageous functionsas amplified in my aforementioned earlier applications.

It will be apparent from the foregoing that the present inventionprovides a new improved steel slag granulation and handling andhydraulic transport system which departs from the materials-handlingconcepts of the abovediscussed current and earlier slag removal systems,thereby avoiding their serious shortcomings and achieving otherimportant objects and advantages as discussed earlier in thisapplication.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

l. A method of handling molten steel slag from a steel mak ing furnacecomprising the steps of pouring molten steel slag into a receptacle;injecting at least one jet of water into said receptacle to interceptsaid molten steel slag and to granulate said slag into particles; saidwater jet having a horizontal extent which is substantially large incomparison to its vertical extent, said water jet being injected intosaid receptacle at a rate of at least about 400 g.p.m., per ton ofmolten slag input per minute, and with a jet velocity ranging from atleast about 25 f.p.s., for a slag input rate of up to 2 tons per minuteto at least about 55-61 f.p.s. for a slag input rate of up to about 8tons per minute; maintaining the water accumulating in said receptacleat a level below said water jet at all times while molten steel slag isbeing poured into said receptacle so that the molten slag interceptssaid water jet above the water accumulated in said receptacle;discharging resultant granulated slag particles from said receptaclewhile granulation of the molten slag is in progress, at a ratesufficiently approximating the rate at which molten slag is poured intosaid receptacle so as to prevent substantial buildup of granulated slagparticles therein; and transporting the granulated slag particles awayfrom said receptacle by pumping the same through a conduit in the formof a water/slag slurry.

2. A method of handling molten steel slag as defined in claim 1 whereinsaid water/slag slurry is pumped through said conduit at a minimumvelocity of about 17 feet per second.

3. A method of handling molten steel slag as defined in claim 1 furtherincluding the step of maintaining said slag/water slurry at up to about17 percent granulated slag to water ratio for said slurry subject toabout a 50 percent surge increase during transportation through saidconduit.

4. A method of handling molten steel slag as defined in claim 1 furtherincluding transferring said granulated slag particles removed from saidreceptacle into an auxiliary receptacle; and wherein the step oftransporting said granulated slag particles comprises pumping saidgranulated slag particles out of said auxiliary receptacle into saidconduit.

5. A method of handling molten steel slag as defined in claim 1 furtherincluding the step of controlling the temperature of the granulated slagslurry being pumped into said conduit at a maximum temperature of aboutF. to 212 F.

6. A method of handling molten steel slag comprising pouring moltensteel slag into a receptacle; injecting at least one jetstream of waterinto said receptacle to intercept said molten steel slag and togranulate the molten slag into particles; the water stream beinginjected with a jet velocity of at least about 25.0 f.p.s., and at leastabout 400 g.p.m., for a molten slag input rate of up to about 2 tons perminute, the water stream being injected with a jet velocity of at leastabout 30 to 36.5 fps, and at least about 500 to 600 g.p.m., for a moltenslag input rate of 2 to about 4 tons per minute, the water stream beinginjected with a jet velocity of at least about 36.5 to 55 fps, and atleast about 1,200 to 1,800 g.p.m., for a slag input rate of 4 to about 7tons per minute, and the water stream being injected with a jet velocityof at least about 55 to 6l fps, and at least about L800 to 2,000 g.p.m.,for a slag input rate of 7-8 tons per minute; maintaining wateraccumulating in said receptacle at a level below said jetstream whilesaid molten steel slag is being poured into the receptacle so that themolten steel slag intercepts said jetstream above said accumulatedwater; removing resultant granulated slag particles from said receptaclewhile the granulation of the molten steel slag is in progress; andtransporting the granulated slag particles away from said receptacle bypumping the same through a conduit in the form of a water/slag slurry.

7. A method of handling molten steel slag as defined in claim 6 whereinsaid slag/water slurry is pumped into said conduit at a maximumtemperature of about 180 F. to 212 F with a slurry velocity of at least17 fps, and with a slag to water ratio of less than approximately 17percent, subject to about a 50 percent surge increase.

8. An apparatus for handling molten steel slag comprising: a slaggranulator including a receptacle; means for feeding molten steel slaginto the receptacle; means for injecting at least one jet stream ofwater into said receptacle so as to intercept said molten steel slag togranulate the molten slag into particles, said injecting means providingsaid water stream at a rate of at least about 400 g.p.m., per ton ofmolten slag input per minute, and with ajet velocity of at least about25 fps, for a molten slag input rate of up to 2 tons per minute, to atleast about 5561 fps, for a slag input rate of up to about 8 tons perminute; means for maintaining water accumulating in said receptacle at alevel below said jetstream while said molten steel slag is being pouredinto the receptacle so that the molten steel slag intercepts saidjetstream above water accumulated in the receptacle; means for removingthe granulated slag from said receptacle while the granulation of themolten steel slag is in progress comprising hydraulic granulated slagslurry transfer means including an auxiliary tank for receiving saidgranulated slag, pump means coupled to said auxiliary tank, anddischarge conduit means connected to said pump means for transportingsaid slag to a remote location in the form of a granulated slag/waterslurry.

9. An apparatus for handling molten slag comprising: a slag granulatorincluding a receptacle; means for feeding molten slag into thereceptacle; means for injecting at least one jetstream of water intosaid receptacle to intercept said molten slag and to granulate said slaginto particles, means for maintaining water accumulating in saidreceptacle at a level below said jetstream while said molten slag isbeing poured into the receptacle so that the molten slag intercepts saidjetstream above water accumulated in the receptacle; means for removingthe granulated slag from said receptacle while granulation is inprogress comprising hydraulic granulated slag-slurry transfer meansincluding discharge conduit means, and pump means connected to saiddischarge conduit means for propelling said slag through said conduit inthe form of a granulated slag/water slurry.

10. Apparatus as defined in claim 9 wherein said slag-slurry transfermeans includes an auxiliary tank for receiving granu- 17 lated slag, andmeans connecting said pump means to said auxiliary tank for removal ofsaid slag from said tank and transportation through said conduit means.

11. An apparatus as defined in claim 9 wherein said slurry transfermeans removes said water and granulated slag slurry from said granulatormeans at substantially the average rate of input into said granulatormeans of water plus slag, and wherein said slurry transfer meansincludes means for varying the water content of said slurry to maintainsaid slurry velocity of at least about 17 feet per second in saiddischarge conduit.

12. An apparatus as defined in claim 11, wherein said slag transfermeans includes means for varying the water content of said slurry tomaintain up to about 17 percent granulated slag to water ratio for saidslurry subject to 50 percent surge increase thereof at said slurryvelocity.

13. An apparatus as defined in claim 9 further comprising means forcontrolling the temperature of the granulated slag slurry fed to theinlet of said pump means to maintain said slurry at a maximumtemperature of less than about 180 F. to 2 12 F.

14. An apparatus for handling molten steel slag comprising: a slaggranulator including a receptacle; means for feeding molten steel slaginto the receptacle; means for injecting at least one jetstream of waterinto said receptacle so as to intercept said molten steel slag togranulate the molten slag into particles, said injecting means providingsaid water stream at a rate of at least about 400 g.p.m., per ton ofmolten slag input per minute, and with a jet velocity of at least about25 f.p.s., for a molten slag input rate of up to 2 tons per minute, toat least about 55-61 f.p.s. for a slag input rate of up to about 8 tonsper minute; means for maintaining water accumulating in said receptacleat a level below said jetstream while said molten steel slag is beingpoured into the receptacle so that the molten steel slag intercepts saidjetstream above water accumulated in the receptacle; means for removingthe granulated slag from said receptacle while the granulation of themolten steel slag is in progress comprising hydraulic granulated slagslurry transfer means for transporting said slag away from saidgranulator in the form of a granulated slag/water slurry.

15. Apparatus for handling molten steel slag comprising: a slaggranulator and hydraulic transfer means as defined in claim 13 whereinsaid injecting means provides said water jetstream at a jet velocity ofat least about 25.0 f.p.s., and at least about 400 g.p.m., for a moltensteel slag input rate of up to about 2 tons per minute, with a jetvelocity of at least about b 30 to 36.5 f.p.s., and at least about 500to 600 g.p.m., for a molten steel slag input rate of 2 to about 4 tonsper minute, with a jet velocity of at least about 36.5 to 55 f.p.s., andat least about 1,200 to 1,800 g.p.m., for a molten steel slag input rateof 4 to about 7 tons per minute, and with a jet velocity of at leastabout 55 to 61 f.p.s., and at least about 1,800 to 2,000 g.p.m., for amolten steel slag input rate of 7-8 tons per minute.

16. Apparatus as defined in claim 9 wherein said injecting meanscomprises jet nozzle means extending horizontally a distance which islarge compared to the vertical extent thereof.

17. An apparatus for handling molten steel slag comprising: a slaggranulator and hydraulic transfer means as defined in claim 9, whereinsaid injecting means provides said water jetstream at a rate of at leastabout 400 g.p.m., per ton of molten steel slag input per minute, andwith a jet velocity of at least about 25 f.p.s., for a molten steel slaginput rate of up to 2 tons per minute, to at least about 55-61 f.p.s.,for a molten steel slag input rate of up to about 8 --1 tons per minute.

18. An apparatus as defined in claim 10 further comprising means forpreventing particles exceeding a predetermined size 18 from enteringsaid auxiliary tank.

19. An apparatus for handling molten slag comprising: a slag granulatorincluding a receptacle; means for feeding molten slag into'thereceptacle; means for injecting at least one jetstream of water intosaid receptacle to intercept said molten sla to granulate the moltenslag into particles, an auxiliary tan coupled to said granulatorreceptacle; means for mamtaining water accumulating in said receptacleat a level below said jetstream while said molten slag intercepts saidjetstream above water accumulated in the receptacle; means fortransferring said granulated slag and water to said auxiliary tank; andhydraulic transport means for transporting the granulated slag away fromauxiliary tank while granulation is in progress in the form of agranulated slag/water slurry.

20. An apparatus as defined in claim 19 further comprising means forpreventing particles exceeding a predetermined size from passing intosaid slag transfer means.

21. An apparatus for handling molten steel slag comprising: a slaggranulator and hydraulic transfer means as defined in claim 13, whereinsaid injecting means provides said water jetstream at a rate of at leastabout 400 g.p.m., per ton of molten steel slag input per minute, andwith a jet velocity of at least about 25 f.p.s., for a molten steel slaginput rate of up to 2 tons per minute, to at least about 55-61 f.p.s.,for a molten steel slag input rate of up to about 8 tons per minute.

22. Apparatus for handling molten steel slag comprising: a slaggranulator and hydraulic transfer means as defined in claim 14 whereinsaid injecting means provides said water jetstream at a jet velocity ofat least about 25 .0 f.p.s., and at least about 400 g.p.m., for a moltensteel slag input rate of up to about 2 tons per minute, with a jetvelocity of at least about 30 to 36.5 f.p.s., and at least about 500 to600 g.p.m., for a molten steel slag input rate of 2 to about 4 tons perminute, with a jet velocity of at least about 36.5 to 55 f.p.s., and atleast about 1,200 to 1,800 g.p.m., for a molten steel slag input rate of4 to about 7 tons per minute, and with a jet velocity of at least about55 to 61 f.p.s., and at least about 1,800 to 2,000 g.p.m., for a moltensteel slag input rate of 7-8 tons per minute.

23. A method of handling molten slag comprising: pouring molten slaginto a receptacle; injecting at least one jetstream of water into saidreceptacle to intercept said molten slag and to granulate the moltenslag into particles; maintaining water accumulating in said receptacleat a level below said jetstream while said molten slag is being pouredinto the receptacle so that the molten slag intercepts said jetstreamabove said accumulated water; removing resultant granulated slagparticles from said receptacle while the granulation of the molten slagis in progress; and transporting the granulated slag particles away fromsaid receptacle by pumping the same through a conduit in the form of awater/slag slurry.

24. An apparatus as defined in claim 19 wherein said hydraulic transfermeans removes said water and granulated slag slurry from said granulatormeans at substantially the average rate of input into said granulatormeans of water plus slag, and wherein said slurry transfer meansincludes means for varying the water content of said slurry to maintaina slurry velocity of at least about 17 feet per second during transportaway from said granulator.

25. An apparatus as defined in claim 24 wherein said hydraulic transfermeans includes means for varying the water content of said slurry tomaintain up to about 17 percent granulated slag to water ratio for saidslurry subject to 50 percent surge increase thereof at said slurryvelocity.

26. An apparatus as defined in claim 25 further comprising means forcontrolling the temperature of the granulated slag slurry to maintainsaid slurry at a maximum temperature of less than about F. to 2l2 F.

2. A method of handling molten steel slag as defined in claim 1 whereinsaid water/slag slurry is pumped through said conduit at a minimumvelocity of about 17 feet per second.
 3. A method of handling moltensteel slag as defined in claim 1 further including the step ofmaintaining said slag/water slurry at up to about 17 percent granulatedslag to water ratio for said slurry subject to about a 50 percent surgeincrease during transportation through said conduit.
 4. A method ofhandling molten steel slag as defined in claim 1 further includingtransferring said granulated slag particles removed from said receptacleinto an auxiliary receptacle; and wherein the step of transporting saidgranulated slag particles comprises pumping said granulated slagparticles out of said auxiliary receptacle into said conduit.
 5. Amethod of handling molten steel slag as defined in claim 1 furtherincluding the step of controlling the temperature of the granulated slagslurry being pumped into said conduit at a maximum temperature of about180* F. to 212* F.
 6. A method of handling molten steel slag comprisingpouring molten steel slag into a receptacle; injecting at least onejetstream of water into said receptacle to intercept said molten steelslag and to granulate the molten slag into particles; the water streambeing injected with a jet velocity of at least about 25.0 f.p.s., and atleast about 400 g.p.m., for a molten slag input rate of up to about 2tons per minute, the water stream being injected with a jet velocity ofat least about 30 to 36.5 f.p.s., and at least about 500 to 600 g.p.m.,for a molten slag input rate of 2 to about 4 tons per minute, the waterstream being injected with a jet velocity of at least about 36.5 to 55f.p.s., and at least about 1,200 to 1,800 g.p.m., for a slag input rateof 4 to about 7 tons per minute, and the water stream being injectedwith a jet velocity of at least about 55 to 61 f.p.s., and at leastabout 1,800 to 2,000 g.p.m., for a slag input rate of 7-8 tons perminute; maintaining water accumulating in said receptacle at a levelbelow said jetstream while said molten steel slag is being poured intothe receptacle so that the molten steel slag intercepts said jetstreamabove said accumulated water; removing resultant granulated slagparticles from said receptacle while the granulation of the molten steelslag is in progress; and transporting the granulated slag particles awayfrom said receptacle by pumping the same through a conduit in the formof a water/slag slurry.
 7. A method of handling molten steel slag asdefined in claim 6 wherein said slag/water slurry is pumped into saidconduit at a maximum temperature of about 180* F. to 212* F., with aslurry velocity of at least 17 f.p.s., and with a slag to water ratio ofless than approximately 17 percent, subject to about a 50 percent surgeincrease.
 8. An apparatus for handling molten steel slag comprising: aslag granulator including a receptacle; means for feeding molten steelslag into the receptacle; means for injecting at least one jet stream ofwater into said receptacle so as to iNtercept said molten steel slag togranulate the molten slag into particles, said injecting means providingsaid water stream at a rate of at least about 400 g.p.m., per ton ofmolten slag input per minute, and with a jet velocity of at least about25 f.p.s., for a molten slag input rate of up to 2 tons per minute, toat least about 55-61 f.p.s., for a slag input rate of up to about 8 tonsper minute; means for maintaining water accumulating in said receptacleat a level below said jetstream while said molten steel slag is beingpoured into the receptacle so that the molten steel slag intercepts saidjetstream above water accumulated in the receptacle; means for removingthe granulated slag from said receptacle while the granulation of themolten steel slag is in progress comprising hydraulic granulated slagslurry transfer means including an auxiliary tank for receiving saidgranulated slag, pump means coupled to said auxiliary tank, anddischarge conduit means connected to said pump means for transportingsaid slag to a remote location in the form of a granulated slag/waterslurry.
 9. An apparatus for handling molten slag comprising: a slaggranulator including a receptacle; means for feeding molten slag intothe receptacle; means for injecting at least one jetstream of water intosaid receptacle to intercept said molten slag and to granulate said slaginto particles, means for maintaining water accumulating in saidreceptacle at a level below said jetstream while said molten slag isbeing poured into the receptacle so that the molten slag intercepts saidjetstream above water accumulated in the receptacle; means for removingthe granulated slag from said receptacle while granulation is inprogress comprising hydraulic granulated slag-slurry transfer meansincluding discharge conduit means, and pump means connected to saiddischarge conduit means for propelling said slag through said conduit inthe form of a granulated slag/water slurry.
 10. Apparatus as defined inclaim 9 wherein said slag-slurry transfer means includes an auxiliarytank for receiving granulated slag, and means connecting said pump meansto said auxiliary tank for removal of said slag from said tank andtransportation through said conduit means.
 11. An apparatus as definedin claim 9 wherein said slurry transfer means removes said water andgranulated slag slurry from said granulator means at substantially theaverage rate of input into said granulator means of water plus slag, andwherein said slurry transfer means includes means for varying the watercontent of said slurry to maintain said slurry velocity of at leastabout 17 feet per second in said discharge conduit.
 12. An apparatus asdefined in claim 11, wherein said slag transfer means includes means forvarying the water content of said slurry to maintain up to about 17percent granulated slag to water ratio for said slurry subject to 50percent surge increase thereof at said slurry velocity.
 13. An apparatusas defined in claim 9 further comprising means for controlling thetemperature of the granulated slag slurry fed to the inlet of said pumpmeans to maintain said slurry at a maximum temperature of less thanabout 180* F. to -212* F.
 14. An apparatus for handling molten steelslag comprising: a slag granulator including a receptacle; means forfeeding molten steel slag into the receptacle; means for injecting atleast one jetstream of water into said receptacle so as to interceptsaid molten steel slag to granulate the molten slag into particles, saidinjecting means providing said water stream at a rate of at least about400 g.p.m., per ton of molten slag input per minute, and with a jetvelocity of at least about 25 f.p.s., for a molten slag input rate of upto 2 tons per minute, to at least about 55-61 f.p.s. for a slag inputrate of up to about 8 tons per minute; means for maintaining wateraccumulating in said rEceptacle at a level below said jetstream whilesaid molten steel slag is being poured into the receptacle so that themolten steel slag intercepts said jetstream above water accumulated inthe receptacle; means for removing the granulated slag from saidreceptacle while the granulation of the molten steel slag is in progresscomprising hydraulic granulated slag slurry transfer means fortransporting said slag away from said granulator in the form of agranulated slag/water slurry.
 15. Apparatus for handling molten steelslag comprising: a slag granulator and hydraulic transfer means asdefined in claim 13 wherein said injecting means provides said waterjetstream at a jet velocity of at least about 25.0 f.p.s., and at leastabout 400 g.p.m., for a molten steel slag input rate of up to about 2tons per minute, with a jet velocity of at least about =b 30 to 36.5f.p.s., and at least about 500 to 600 g.p.m., for a molten steel slaginput rate of 2 to about 4 =tons per minute, with a jet velocity of atleast about 36.5 to 55 f.p.s., and at least about 1,200 to 1,800 g.p.m.,for a molten steel slag input rate of 4 to about 7 tons per minute, andwith a jet velocity of at least about 55 to 61 f.p.s., and at leastabout 1,800 to 2,000 g.p.m., for a molten steel slag input rate of 7-8tons per minute.
 16. Apparatus as defined in claim 9 wherein saidinjecting means comprises jet nozzle means extending horizontally adistance which is large compared to the vertical extent thereof.
 17. Anapparatus for handling molten steel slag comprising: a slag granulatorand hydraulic transfer means as defined in claim 9, wherein saidinjecting means provides said water jetstream at a rate of at leastabout 400 g.p.m., per ton of molten steel slag input per minute, andwith a jet velocity of at least about 25 f.p.s., for a molten steel slaginput rate of up to 2 tons per minute, to at least about 55-61 f.p.s.,for a molten steel slag input rate of up to about 8 =l tons per minute.18. An apparatus as defined in claim 10 further comprising means forpreventing particles exceeding a predetermined size from entering saidauxiliary tank.
 19. An apparatus for handling molten slag comprising: aslag granulator including a receptacle; means for feeding molten slaginto the receptacle; means for injecting at least one jetstream of waterinto said receptacle to intercept said molten slag to granulate themolten slag into particles, an auxiliary tank coupled to said granulatorreceptacle; means for maintaining water accumulating in said receptacleat a level below said jetstream while said molten slag intercepts saidjetstream above water accumulated in the receptacle; means fortransferring said granulated slag and water to said auxiliary tank; andhydraulic transport means for transporting the granulated slag away fromauxiliary tank while granulation is in progress in the form of agranulated slag/water slurry.
 20. An apparatus as defined in claim 19further comprising means for preventing particles exceeding apredetermined size from passing into said slag transfer means.
 21. Anapparatus for handling molten steel slag comprising: a slag granulatorand hydraulic transfer means as defined in claim 13, wherein saidinjecting means provides said water jetstream at a rate of at leastabout 400 g.p.m., per ton of molten steel slag input per minute, andwith a jet velocity of at least about =25 f.p.s., for a molten steelslag input rate of up to 2 tons per minute, to at least about 55-61f.p.s., for a molten steel slag input rate of up to about 8 tons perminute.
 22. Apparatus for handling molten steel slag comprising: a slaggranulator and hydraulic transfer means as defined in claim 14 whereinsaid injecting means provides said water jetstream at a jet velocity ofat least about 25.0 f.p.s., and aT least about 400 g.p.m., for a moltensteel slag input rate of up to about 2 tons per minute, with a jetvelocity of at least about 30 to 36.5 f.p.s., and at least about 500 to600 g.p.m., for a molten steel slag input rate of 2 to about 4 tons perminute, with a jet velocity of at least about 36.5 to 55 f.p.s., and atleast about 1,200 to 1,800 g.p.m., for a molten steel slag input rate of4 to about 7 tons per minute, and with a jet velocity of at least about55 to 61 f.p.s., and at least about 1,800 to 2,000 g.p.m., for a moltensteel slag input rate of 7-8 tons per minute.
 23. A method of handlingmolten slag comprising: pouring molten slag into a receptacle; injectingat least one jetstream of water into said receptacle to intercept saidmolten slag and to granulate the molten slag into particles; maintainingwater accumulating in said receptacle at a level below said jetstreamwhile said molten slag is being poured into the receptacle so that themolten slag intercepts said jetstream above said accumulated water;removing resultant granulated slag particles from said receptacle whilethe granulation of the molten slag is in progress; and transporting thegranulated slag particles away from said receptacle by pumping the samethrough a conduit in the form of a water/slag slurry.
 24. An apparatusas defined in claim 19 wherein said hydraulic transfer means removessaid water and granulated slag slurry from said granulator means atsubstantially the average rate of input into said granulator means ofwater plus slag, and wherein said slurry transfer means includes meansfor varying the water content of said slurry to maintain a slurryvelocity of at least about 17 feet per second during transport away fromsaid granulator.
 25. An apparatus as defined in claim 24 wherein saidhydraulic transfer means includes means for varying the water content ofsaid slurry to maintain up to about 17 percent granulated slag to waterratio for said slurry subject to 50 percent surge increase thereof atsaid slurry velocity.
 26. An apparatus as defined in claim 25 furthercomprising means for controlling the temperature of the granulated slagslurry to maintain said slurry at a maximum temperature of less thanabout 180* F. to -212* F.